--- reaver-1.4.org/src/libwps/libwps.h
+++ reaver-1.4/src/libwps/libwps.h
@@ -17,6 +17,7 @@
 #include <stdio.h>
 #include <string.h>
 #include <arpa/inet.h>
+#include <sys/types.h> /* u_char */
 
 #define LIBWPS_MAX_STR_LEN 256
 
